Bad weather delays synchronised-satellites’ launch

After deployment, the micro-sats will be positioned in a “string of pearls” constellation, demonstrating the ability to position micro-sats to perform simultaneous multi-point measurements

(Image: NASA)

A Pegasus XL will deliver the three micro-satellites into low Earth orbit, after itself hitching a ride high into the atmosphere on a L-1011 aircraft

(Image: NASA)

NASA hopes to launch a trio of television set-sized satellites into a string-of-pearls orbit around the Earth on Wednesday , after poor weather delayed lift-off on Tuesday.

Space Technology 5 (ST5) is a 90-day technology demonstration mission developed under NASA’s New Millennium Programme, which could pave the way for future missions involving dozens of such “micro-satellites”, or even smaller “nano-satellites”.

Advertisement

The three 25-kilogram ST5 satellites will use a small low-cost rocket – Orbital Science Corporation’s Pegasus XL – to reach low-Earth orbit. The Pegasus XL will itself hitch a ride into the sky beneath an L-1011 airplane, which will take off from Vandenberg Air Force Base in California, US. Once released high in the sky by the L-1011, the Pegasus rocket will ignite and boost the three satellites into orbit.

Poor weather conditions scuppered the launch on Tuesday and the mission was delayed until Wednesday, when the chances of precipitation, thunderstorms and turbulence are expected to decrease significantly.

Swarms of spacecraft

ST5 was selected as a New Millennium technology development and validation mission in August 1999. “The lessons learned from the development and flight of ST5’s three full-service micro-spacecraft constitute a major step toward the use of ‘constellations’ or ‘swarms’ of small spacecraft to accomplish science that cannot be done with a single spacecraft, no matter how capable,” says Jim Slavin, the mission’s project scientist.

The three “micro-sats” will follow a synchronised elliptical orbit around Earth, coming to within 300 kilometres of the planet at times and extending out as far as 4500 kilometres at others.

The satellites will study the Earth’s inner magnetosphere, the invisible shell that protects the planet from harmful radiation and particles that spews from the Sun’s surface in flares and coronal mass ejections. But it is not a perfect barrier and, by studying it, scientists hope to learn how to better guard against the space weather that gets through.

The ST5 satellites are equipped with full suites of miniaturised instruments, including tiny magnetometers, antennae, microthrusters, transponders and low voltage electronics, which are all technology tests themselves. The mission calls for the satellites to operate in a fully autonomous mode for a week.

“We’re trying to point the way toward missions of tens or hundreds of satellites flying across a wider region of space,” Candace Carlisle, ST5 deputy project manager from Goddard Space Flight Center told New Scientist. “If you want to look across a wide region of space, then you want a lot of little data points.”